However, security researcher Tod Beardsley of Rapid7 told Computerworld that today's out-of-band update does take care of the issue.

"It appears that it's effective in blocking the exploit," said Beardley.

According to an Oracle security advisory, if an unpatched system were attacked using any of the three related Java holes, "these vulnerabilities can provide a malicious attacker the ability to plant discretionary binaries onto the compromised system, e.g. the vulnerabilities can be exploited to install malware, including Trojans, onto the targeted system."

Security firm FireEye, which publically disclosed the Java vulnerability earlier this week, said that it had seen attackers suing a Chinese IP addresses use this hole to infect targeted systems with the Poison Ivy Trojan.

However, with the online release of a proof-of-concept video on how to exploit the vulnerability, security experts were warning that the amount of attacks was predicted to rise. In response, and without a solution readily available from Oracle, many (including Microsoft) had been advising users to completely disable the Java plugin for Web browsers.